To accommodate daily recurring environmental changes, animals show cyclic variations in behaviour and physiology, which include prominent behavioural states such as sleep-wake cycles but also a host of less conspicuous oscillations in neurological, metabolic, endocrine, cardiovascular and immune functions. Circadian rhythmicity is created endogenously by genetically encoded molecular clocks, whose components cooperate to generate cyclic changes in their own abundance and activity, with a periodicity of about a day. Throughout the body, such molecular clocks convey temporal control to the function of organs and tissues by regulating pertinent downstream programmes. Synchrony between the different circadian oscillators and resonance with the solar day is largely enabled by a neural pacemaker, which is directly responsive to certain environmental cues and able to transmit internal time-of-day representations to the entire body. In this Review, we discuss aspects of the circadian clock in Drosophila melanogaster and mammals, including the components of these molecular oscillators, the function and mechanisms of action of central and peripheral clocks, their synchronization and their relevance to human health.

中文翻译：

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昼夜节律的分子机制和生理重要性。

为了适应日常不断变化的环境变化，动物表现出行为和生理上的周期性变化，其中包括突出的行为状态（例如睡眠-觉醒周期），但在神经，代谢，内分泌，心血管和免疫功能方面也出现了一些不那么明显的振荡。昼夜节律性是由遗传编码的分子钟内源性地产生的，其组成部分相互配合以产生自身丰度和活性的周期性变化，周期约为一天。通过调节相关的下游程序，这种分子钟在整个人体中传达了对器官和组织功能的时间控制。神经起搏器很大程度上可以使不同的昼夜节律振荡器之间的同步以及与太阳日的共振得以实现，它直接响应某些环境提示，并能够将内部的时间表示传递给整个身体。在这篇综述中，我们讨论了果蝇和哺乳动物中生物钟的各个方面，包括这些分子振荡器的组成，中央和外围生物钟的功能和作用机制，它们的同步性及其与人类健康的相关性。